* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --bg-app: #1e1e1e;
    --bg-pane: #252526;
    --bg-header: #333333;
    --text-primary: #d4d4d4;
    --text-secondary: #808080;
    --border: #3c3c3c;
    --accent: #0e639c;
    --accent-hover: #1177bb;
    --success: #4ec9b0;
}

body {
    font-family: 'Consolas', 'Monaco', monospace;
    background: var(--bg-app);
    color: var(--text-primary);
    min-height: 100vh;
}

.app-container {
    display: flex;
    flex-direction: column;
    height: 100vh;
}

.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.5rem 1rem;
    background: var(--bg-header);
    border-bottom: 1px solid var(--border);
    flex-wrap: wrap;
    gap: 0.5rem;
}

.header h1 {
    font-size: 1rem;
    font-weight: 500;
}

.header-controls {
    display: flex;
    gap: 0.5rem;
}

.btn-secondary {
    padding: 0.4rem 0.8rem;
    border: none;
    border-radius: 4px;
    font-size: 0.8rem;
    cursor: pointer;
    transition: all 0.2s;
    background: var(--bg-pane);
    color: var(--text-primary);
    border: 1px solid var(--border);
}

.btn-secondary:hover {
    background: var(--border);
}

.main-content {
    flex: 1;
    display: flex;
    overflow: hidden;
}

/* ペイン共通 */
.editor-pane, .preview-pane {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.editor-pane {
    border-right: 1px solid var(--border);
}

.pane-header {
    padding: 0.4rem 0.75rem;
    background: var(--bg-header);
    border-bottom: 1px solid var(--border);
    font-size: 0.8rem;
    color: var(--text-secondary);
}

/* エディタ */
#editor {
    flex: 1;
    padding: 0.75rem;
    background: var(--bg-pane);
    border: none;
    color: var(--text-primary);
    font-family: 'Consolas', 'Monaco', monospace;
    font-size: 0.9rem;
    resize: none;
    outline: none;
    line-height: 1.6;
}

#editor::placeholder {
    color: var(--text-secondary);
}

/* プレビュー */
.preview-content {
    flex: 1;
    padding: 0.75rem;
    background: var(--bg-pane);
    overflow-y: auto;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    font-size: 0.95rem;
    line-height: 1.7;
}

/* Markdownスタイル */
.preview-content h1 {
    font-size: 1.8rem;
    border-bottom: 1px solid var(--border);
    padding-bottom: 0.3rem;
    margin: 1rem 0 0.5rem;
    color: var(--success);
}

.preview-content h2 {
    font-size: 1.4rem;
    border-bottom: 1px solid var(--border);
    padding-bottom: 0.2rem;
    margin: 1rem 0 0.5rem;
    color: var(--success);
}

.preview-content h3 {
    font-size: 1.2rem;
    margin: 1rem 0 0.5rem;
    color: var(--success);
}

.preview-content h4, .preview-content h5, .preview-content h6 {
    font-size: 1rem;
    margin: 0.8rem 0 0.4rem;
    color: var(--success);
}

.preview-content p {
    margin: 0.5rem 0;
}

.preview-content strong {
    color: #dcdcaa;
}

.preview-content em {
    font-style: italic;
    color: #ce9178;
}

.preview-content a {
    color: var(--accent);
    text-decoration: none;
}

.preview-content a:hover {
    text-decoration: underline;
}

.preview-content code {
    background: var(--bg-app);
    padding: 0.15rem 0.4rem;
    border-radius: 3px;
    font-family: 'Consolas', monospace;
    font-size: 0.85em;
    color: #ce9178;
}

.preview-content pre {
    background: var(--bg-app);
    padding: 0.75rem;
    border-radius: 4px;
    overflow-x: auto;
    margin: 0.5rem 0;
    border: 1px solid var(--border);
}

.preview-content pre code {
    padding: 0;
    background: transparent;
    color: var(--text-primary);
}

.preview-content blockquote {
    border-left: 3px solid var(--accent);
    padding-left: 1rem;
    margin: 0.5rem 0;
    color: var(--text-secondary);
}

.preview-content ul, .preview-content ol {
    padding-left: 1.5rem;
    margin: 0.5rem 0;
}

.preview-content li {
    margin: 0.25rem 0;
}

.preview-content hr {
    border: none;
    border-top: 1px solid var(--border);
    margin: 1rem 0;
}

.preview-content img {
    max-width: 100%;
    height: auto;
}

.preview-content table {
    border-collapse: collapse;
    width: 100%;
    margin: 0.5rem 0;
}

.preview-content th, .preview-content td {
    border: 1px solid var(--border);
    padding: 0.5rem;
    text-align: left;
}

.preview-content th {
    background: var(--bg-header);
}

/* 目次（TOC） */
.preview-content .toc {
    background: var(--bg-app);
    border: 1px solid var(--border);
    border-radius: 4px;
    padding: 0.75rem;
    margin: 0.5rem 0;
}

.preview-content .toc-title {
    font-weight: bold;
    color: var(--success);
    margin-bottom: 0.5rem;
    font-size: 0.9rem;
}

.preview-content .toc ul {
    list-style: none;
    padding-left: 0;
    margin: 0;
}

.preview-content .toc li {
    margin: 0.25rem 0;
    font-size: 0.9rem;
}

.preview-content .toc a {
    color: var(--text-primary);
}

.preview-content .toc a:hover {
    color: var(--accent);
}

/* フッター */
.footer {
    padding: 0.4rem 1rem;
    background: var(--bg-header);
    border-top: 1px solid var(--border);
    font-size: 0.7rem;
    color: var(--text-secondary);
}

/* トースト */
.toast {
    position: fixed;
    bottom: 1rem;
    right: 1rem;
    background: var(--success);
    color: var(--bg-app);
    padding: 0.5rem 1rem;
    border-radius: 4px;
    opacity: 0;
    transform: translateY(10px);
    transition: all 0.2s;
}

.toast.show {
    opacity: 1;
    transform: translateY(0);
}

/* レスポンシブ */
@media (max-width: 768px) {
    .main-content {
        flex-direction: column;
    }

    .editor-pane {
        border-right: none;
        border-bottom: 1px solid var(--border);
        height: 50%;
    }

    .preview-pane {
        height: 50%;
    }
}